Prefolding device



y 1959 M. L. BELTON ET AL 2,894,434

PREFOLDING DEVICE Filed Jan. 6. 1955 2 Sheets-Sheet 1 Q3 FIG I l7 I? O l2 hma rme Mum/c5 4 3,54 my 24117 6 1 01/40/14 a 56 55 e 5e Patented July 14, 1959 PREFOLDING DEVICE Maurice L. Belton and Harold E. Rowand, Bogalusa, La., assignors, by mesne assignments, to Crown Zellerbach l (iIorptliiration, San Francisco, Calif., a corporation of eva a Application January 6, 1955, Serial No. 480,248,

4 Claims. (Cl..93-49) This invention appertains in general to rotary means for prefolding flaps on container blanks and more particularly to a device of the type described which may be readily attached to existing container fabricating equipment. v

Containers formed of fibreboard and similar materials are generally manufactured from flat, scored and slotted blanks fabricated on high speed rotary equipment. customary manner of sealing the container walls together to provide for erection of the blank is by means of a relatively narrow stitch or glue flap foldably connected to one of the container side walls along a hinge or score line. The container is erected by folding the blank about corner defining scores so that the glue or stitch flap may be attached to a free margin of an adjacent container side wall. Due to the resiliency and stiffness of the fibreboard and other material, the glued or stitched seal is often broken or damaged as the container is erected. This is due to the tendency of the sealing flap to fail to bend about the score line between it and the adjacent side wall. It is undesirable to more deeply score or crease the fold line which provides the hinge connection for the sealing flap since this would unduly weaken the container so as to cause failure of the container during use. It is, therefore, desirable to provide other means to afford a more flexible sealing flap without unnecessarily weakening the container. A desirable means of accomplishing this is to pre-bend or fold the sealing flap while the blank is in flatwise condition and before it is sealed and erected into a container.

In order to be commercially desirable, means for prefolding the sealing flap should be simple and inexpensive to manufacture and should be readily adapted to be attached to existing blank-forming equipment, such as rotary scoring machines and printer-slotters. It should also be easily adjustable to accommodate a Wide variety of blank sizes. It is, therefore, an object of this invention to provide a simple device which may be readily attached to existing blank forming machinery and which may be easily and quickly adjusted to operate on various size container blanks.

Another object is to provide a container blank sealing flap prefolding device having adjustable rollers or wheels which are offset about the score line defining the hinge connection of the sealing flap.

A further object is to provide a device of the type described which requires no external source of power and which is actuated by the movement of the container blank.

Other objects and advantages of this invention will be apparent upon a full and complete understanding of the construction and operation of this device.

The invention also consists in the parts, arrangements and combinations of parts hereinafter described and claimed. The accompanying drawings form a partof this specification and like numerals and symbols therein appearing refer to like parts wherever they occur.

Fig. 1 is a side elevation illustrating a prefolding device embodying the invention shown attached to a typical printer-slotter machine;

Fig. 2 is a fragmentary top view of a preferred embodiment of the invention shown attached to a printer-slottermachine;

Fig. 3 is a fragmentary top view through section 3-3 v of Fig. 2;

Fig. 4 is a fragmentary side view through section 44 of Fig. 2;

.Fig. 5 is a fragmentary side view through section 55 of Fig. 2;

Fig. 6 is a perspective view of a containerblank em ploying a sealing flap adapted to be prefolded on'the embodiment of the invention illustrated;

Fig. 7 is a detailed drawing of a guide holder member employed in the invention;

Fig. 8 is a detailed drawing of a blank in the embodiment of the invention illustrated; and

Fig. 9 is a detailed drawing of a plow member employed in the embodiment of the invention illustrated.

Fig. 1 illustrates a commercial device for printing, scoring and slotting fibreboard. container blanks, known in the art as a printer-slotter, A. The general features of a typical printer-slotter are well known and may be found, for example, in Patent No. 1,850,802 issued to Samuel M. Langston et al. on March 22, 1932. The function of the printer-slotter is to receive a fibreboard or other containerblank and print, score and slot and blank in a continuing operation. The feed table of the device is illustrated at 11, and guide members which properly, horizontally align the sheet to be fed into the machine are indicated at 12. The container blanks or sheets are fed into the machine by means of a horizontally oscillating feed lever 13, which forwards the sheets between a series of rotating feed rollers 14. Adjacent the feed rollers 14 are two pairs "of printing units, each comprising an upper printing cylinder 15 and a lower pressure'cylinder 16. Each upper printing cylinder 16 is inked by a series of fountain rolls 17. A pair of scoring rolls 18 adjacent one of the pairs of printing cylinders provides the creases for the container. Adjacent the scoring rollers 18 a slotting mechanism consisting of a top slotting roll 19 and a bottom slotting roll 20 is adapted to slot the container blank. The printer-slotter machine A may be driven by an electric motor (not illustrated) or any other desired motion imparting means.

Prefolding device B is located at the take-off end of the machine. The prefolding device, as shown in Fig. 4, is mounted closely adjacent the slotting rolls 19 and 20. Since the slotting rolls are relatively narrow in width, there are substantial spaces between adjacent rolls which permit the prefolding device B to be mounted out of alignment with the slotting rolls 19 and 20. The prefolding device B comprises a member such as. a folding wheeli21 rotatably mounted on a fixed horizontal top shaft 22 which, in turn, is rigidly secured to a vertical mounting bracket 23. The bracket 23 is adjustably fixed to a horizontal shaft 24 fixed to the printer-slotter machine A. The shaft 24 is provided with a key 25 which prevents accidental rotary movement of the mounting bracket 23. The mounting bracket 23 is adjustably fixed to the shaft 24 by means of a set screw 26.

guide employed The purpose of the groove 29 in the embodiment of the invention described is to prevent accidental movement of the plate 22 about the threaded fastening 31.

A fixed bottom shaft 32 is mounted through the lower portion of the mounting bracket 23 and fixedly secured to the mounting collar 33 which isprovided with an adjustable set screw 34. The bottom shaft 32 may be readily adjusted by loosening the set screw 34 and moving the shaft through the mounting bracket 23 and the mounting-collar 33. A member such as a bottompressure wheel 3'5'is rotatably mounted on the end of the bottom shaft32. The fold wheel 21.is provided with a relieved or rounded corner 36 positioned adjacent the bottom pressure Wheel 35. In the embodiment of the invention illustrated; the corners 37 of thebottompressure Wheel 35 are square.

A pl'ow member 38, as shown in detail in Fig. 9, is provided with a rounded plow portion 39'and a plow bracket plate 40. The plow member 38 is rigidly connected'to the bottom shaft 32 by means ofthreaded fastenings 41 which extend through openings 42 in the plow bracket plate 40. The plow member 38 may be adjusted in a vertical plane by loosening the set screws 34 and rotating the bottom shaft 32 into the desired position.

A stripper guide 43 is also slidably mounted on the shaft 24 and is provided with an adjustable thumb screw. 44. The stripper guide 43 is usually part of the standard equipment of commercial printer-slotters. A guide bar 45, illustrated in Fig. 7, is slidably attached to the stripper guide 43 within a circular groove 46 as best shown in Fig. 3. opening adjacent the circular groove 46 to permit adjustment of'the guide bar 45. The end of the guide bar 45 adjacent the slotting rolls is provided with a guide bracket 48 with bracket openings 49 extending thereto. A tapered guide plate 50, as shown in detail in Fig. 8, is provided with a circular opening 51 and an arcuate opening 52 both attached to fit in registering relation over the bracket openings 49. The guide plate 50 is pivotally secured to the guide bracket 48 by means of threaded fastenings 53 which extend through the registering openings in the guide bracket 48 and the guide plate 50. By loosening the threaded fastening 53, the guide plate 50 may be pivoted about the fastening 53 in the registering openings 49 and 51 for vertical adjustment.

It is contemplated that the printer-slotter machine will produce container blanks having a configuration as illustrated in Fig. 6. The typical blank illustrated is provided with upstanding side walls 54 connected together along corner scores 55. End flaps 56 are defined in-part by end scores 57. End slots 58, in alignment with corner scores 55, define the side edges of the end flaps 56. A securing flap 59 is foldably connected to one of the side walls 54 along a corner score 55.

The completed blank ordinarily emerges from the printer-slotter machine as illustrated in Fig. 6. In order to assemble the blank, it is necessary to fold the two end-most side walls 54 about their adjacent corner scores inwardly in flatwise relationship with their adjacent sidewall 54. The flap 59 is then secured to the adjacent,

margin of the opposing, endmost side wall 54, by stitches, glue or any other suitable means. The side walls 54 of the container are then erected into rectangular, tubular relation. But to the stiffness and resilience of the corrugated and solid fibreboard usually employed in containers of this type, the relatively narrow glue .flap tends to fail or'break at its adjacent corner score 55 thereby causing. the glue or stitches, which secure the securing flap 59 in place, to tear 'or fail completely. It isbelieved that it will be apparent upon a further reading of the flexingthe adjacentcorner score 55 so as to facilitate A guide set screw 47 is threaded into a tapped bending of the securing flap 59 when the container is erected into position.

The embodiment of the prefolding device described is ordinarily attached to the shaft 24 after the other parts of the machine have been adjusted, it being necessary to align the prefolding device with respect to the completed blank as it emerges from the printer-slotter. As best shown in Figs. 2 and 3, as the blank leaves the slottingheads or slotting rolls 19 and.20, the side walls, the,

way its Width. The folding wheel is then vertically ad+ justed by means of the threaded fastening 31 which permits the adjustable plate 27 to be moved within the groove 29. The folding wheel 21' is adjusted until the outer edge of the rounded corner 36 is below the top surface of the container blank a distance preferably equal to the thickness of the blank material. The position of the folding wheel with respect to the container blank, as.

described, may be modified for different materials, for example, if a heavier, more resilient material were employed it might be desirable to lower the folding wheel 21 and move it outwardly toward the free side edge of the glue flap 59. The bottom pressure wheel is moved into position by loosening the set screw 34 and sliding.

the bottom shaft 22 into position as indicated in Figs. 2 and 3. In the preferred adjustment the bottom pressure wheel 35 is located so that the corner 37, positioned adjacent the rounded corner 36 of the folding wheel, is-

vertically beneath the corner score 55 of the glue flap 59. The bottom shaft 32 is rotated until the plow portion 39 is in horizontal, contacting alignment with the underface of the container blank, for example, as shown in Fig. 4. The set screw 34 is then tightened in place to hold the bottom shaft 32 in position.

Lastly, the threaded fastening extending through the arcuate opening 52 is loosened to permit the guide plate 50 to be pivoted downwardly until the lower rounded corner edge 60, shown in Fig. 8, is slightly above the top surface of the container blank. The threaded fastenings 53 extending through the arcuated opening is then tightened into place and then the prefolding device is ready for use.

The uncut fibreboard material is placed on the feed table 11, of the printer-slotter A. The oscillating feed member 13 forwards the fibreboard material between the first pair of rolls 14 which continuously advance the blank between the two pairs of printing cylinders 15 and the bottom pressure roll 16. Later, pairs of feed rollers. 14 advance the printed sheet through the scoring rolls.

further, it passes beneath the corner edge 60 of the guide plate 50. Continuing, the glue flap 59, is engaged by the folding wheel 21 which forces it angularly downwardly breaking, the adjacent corner score 55. The bottom pressure wheel 35 is mounted adjacent the folding Wheel 21 thereby supporting the container side wall 54 adjacent the securing flap 59 being folded by the .wheel.

21. Since both they folding wheel 21 and the bottom pressure wheel .35 are freely rotatable, themovementof.

the blank will cause the wheels to, rotate as the container blank passes therebetween. The freely rotating wheels do not in any way impede or hinder the free movement The embodiment of the prefolding device described is fully adjustable and may be fully and quickly adjusted for various widths and thickness of the containerblanks. It also may be mounted on existing equipment without extensive modification. It is thereby understood that the particular embodiment of the invention described is illustrative and not restrictive. The invention may be susceptible of embodiment in other modified forms. All modifications which are similar or equivalent hereto come equally within the scope of the claims next appearing.

What we claim is:

1. A machine having driving means for moving a sheet of fibreboard material substantially horizontally through the machine to form a box blank having an end flap hingedly connected thereto along a score line, the machine having a box blank output end with a pair of upper and lower transverse, substantially horizontal members disposed respectively above and below the box blank, the combination of an end flap prefolding means comprising a folding wheel and a backing wheel, both wheels being freely, rotatably mounted on individual shafts disposed in substantially parallel relation to the box blank and positioned at right angles to the corner score lines of the box blank, the shaft supporting said folding wheel being adjustably fixed to the upper horizontal member disposed at the output end of the machine, the periphery of the folding wheel being disposed in contacting alignment with the upper face of the end flap in spaced relation from the corner score line to bend the end flap about the score line out of the plane of the container blank, the shaft supporting the backing wheel being adjustably fixed to the lower horizontal member disposed at the output end of the machine, the periphery of the backing wheel being disposed in contacting relation against the lower face of the box blank in closely spaced relation to the corner score line to maintain the box blank portions adjacent the corner score line in a plane of the remainder of the box blank as the blank passes horizontally between the folding and backing wheels, the folding and backing wheels being adapted to freely rotate as the box blank passes therebetween, a pair of upper and lower guide members the lower guide member having a fixed horizontal part adapted to engage the underface of the container blank in spaced relation from the end flap thereon, and the upper guide member being vertically adjustable to slidably engage the top surface of the container blank in substantial vertical alignment with said backing wheel.

2. A machine having means for moving a sheet of fibreboard material substantially horizontally through the machine to form a box blank having an end flap hingedly connected thereto along an end score line, the machine having a box blank output end with a pair of upper and lower transverse, substantially horizontal members disposed respectively above and below the box blank, the combination of an end flap prefolding device comprising a vertically staggered folding wheel and a backing wheel, both wheels being freely, rotatably mounted on individual shafts disposed in substantially parallel relation to the box blank and positioned at right angles to the and score line of the box blank, the shaft sup-porting said folding wheel being adjustably fixed to the upper horizontal member disposed at the output end of the machine, the side edge of the folding wheel being relieved to provide a smooth surface below the upper face of the box blank to contact the upper face of the end flap in spaced relation from the end score line to bend the end flap about the score line out of the plane of the container 5 blank, the shaft supporting the backing wheel being adjustably fixed to the lower horizontal member disposed in the output end of the machine, the periphery of the backing wheel being disposed in contacting relation to the end score line to maintain the box blank portions adjacent the end score line in the plane of the remainder of the box blank as the blank passes horizontally between the folding and backing wheels, the folding and backing wheels being adapted to freely rotate as the box blank passes therebetween, a pair of upper and lower guide members to guide the blanks between the folding and backing wheels, the lower guide member having afixed horizontal part adapted to engage the underface of the container blank in spaced relation from the'end flap thereon, and the upper guide member being vertically adjustable to slidably engage the top surface of the container blank in substantial vertical alignment with said backing wheel.

3. A machine having means for moving a sheet of fibreboard material substantially horizontally through the machine and scoring and slotting the material to form a box blank having side walls defined in part by corner forming scores, and foldably connected end flaps defined in part by slots co-extensive with the corner forming scores, the box blank moving horizontally through the machine in the direction of the corner forming scores, the box blank having a relatively narrow end flap hingedly connected thereto along an end corner score line, the machine having a box blank output end with a pair of upper and lower transverse, substantially horizontal members disposed respectively above and below the box blank, the combination of an end flap prefolding device comprising a vertically staggered folding wheel and a backing wheel, both wheels being freely, rotatably mounted on individual shafts disposed in substantially parallel relation to the box blank and positioned at right angles to the end score line of the box blank, the shaft supporting said folding wheel being vertically and horizontally adjustably fixed to the upper horizontal member disposed at the output end of the machine, the side edge of the folding Wheel being relieved to provide a smooth surface to contact the upper face of the end flap in spaced relation from the end score line to bend the end flap about the score line out of the plane of the container blank, the shaft supporting the backing wheel being adjustably fixed to the lower horizontal member disposed in the output end of the machine, the periphery of the backing wheel being disposed in contacting relation against the lower face of the box blank in closely spaced relation to the end score line to maintain the box blank portions adjacent the end score line in the plane of the remainder of the box blank as it passes horizontally between the folding and backing wheels, the folding and backing wheels being adapted to freely rotate as the box blank passes therebetween, a pair of upper and lower guide members to guide the blanks between the folding and backing wheels, the lower guide member having a fixed horizontal part adapted to engage the underface of the container blank in spaced relation from the end flap thereon, and the upper guide member being vertically adjustable to slidably engage the top surface of the container blank in substantial vertical alignment with said backing Wheel.

4. A machine having driving means for moving a sheet of fibreboard material substantially horizontally through the machine to form a box blank having an end flap hingedly connected thereto along a score line, the machine having a box blank output end with a pair of upper and lower transverse, substantially horizontal members disposed respectively above and below the box blank, the combination of an end flap prefolding means comprising a folding member and a backing member, both members being individually mounted in substantially parallel relation to the box blank and positioned adjacent the corner score line defining the end flap of the box blank, the

ber being-disposedincontacting alignment. withthe upper-- face ofthe. end flap'in spaced relation from the said corner score line to bend the end} flap about the score line out of the plane of the container blank, the mount. supporting the backing memberbeing adjustably fixed to the lower horizontal member disposed at'the output end v of: the machine, thesurface of the backing member being disposed in contacting relation against the lower face of the box blank in closely spaced relation to the saidcorner score line to maintain the box blank portions adjacent the said corner score line inaplane ofthe re mainder of the box blank as .the blank passes horizontally between the folding and backing; members, the folding and backing membersbeing adapted to engage the box.- blank which passes therebetween, a pair of upper andlower guide members, the lower guide member. adapted to'engage the underface, of the container blank in spaced relation from the end flap thereon, andthe upper guidemember being adaptable to slidably engage the top surface of the container blank in substantial vertical alignment with said backing member.

References Cited inthe file of this patent.

UNITED STATES PATENTS 558,883 Walton Apr. 21, 1896. 1,882,531 Ungar Oct. 11, 1932 2,655,082 Amyx et al Oct. 13, 1953 2,669,167 Behl Feb. 16, 19.5.4. 

